Babbitt-bronze-aluminum bonding process



Nov. 10, 1959 R. R. FIKE ETI'AL 0 BABBITT-BRONZE-ALUMINUM BONDING PROCESS Filed June 27, 1955 fnuerzz b 715'" Gler'i J P L'Zo 21.5

tained.

United tates Patent Ofiice 2,911,708 Patented Nov. 10, 1959.

BABBl'IT-BRONZE-ALUMINUM BONDING PROCESS Russell R. Fike, Euclid, and Albert J. Pilous, Cleveland, Ohio, assignors to Borg-Warner Corporation, Chicago, 111., a corporation of Illinois Application June 27, 1955, Serial No. 518,046

11 Claims. (Cl. 29149.5)

This invention relates to the process of bonding metals of different characteristics and more particularly to a process of producing aluminum to bronze to babbitt bonds and to the composite articles so produced.

In our co-pending application, Serial No. 514,536, filed June 10, 1955, we have described a process of bonding aluminum and its alloys to heavier metals, such as copper-lead alloys, known as bronzes, and the articles so produced. Our co-pending application describes the difliculties hereinbefore encountered in making such bonds and the process by which these difficulties are successfully overcome, which process essentially comprises the bonding of the dissimilar metals by means of a bonding agent comprising tin. The purpose of the bonds therein described is to produce light weight structures, such as bearings and pump bushings, having copper-lead or bronze bearing surfaces, such bearing surfaces being preferable to those of aluminum.

It is well-known that bronze bearing surfaces have a tendency. to seize during operation due to. the lack of a uniform coating of oil or lubricantthereon, sothat metal-to-metal contact between bearing surfaces is main- -The seizure of such bearings may be successfully overcome by providing the bronze bearing surface with a thin layer of babbittthereon. Also, foreign particles in contact with bronze bearing surfaces have a tendency to score the bearing surface thereby reducing the life of the bearing. Babbitts are possessed of a characteristic known as embedability, that is, foreign particles may easily become embedded in the babbitt and thereby prevent the scoring of the bearing surface. Therefore, thejprincipal object of this invention is to provide a process of producing an aluminum to bronze to babbitt bond which provides a bond between the aluminum and bronze having maximum strength and ductility and with a babbitt layer on the bronze.

More particularly, the object of this invention is to provide a process of producing a bearing comprising an aluminum backing, a bronze member bonded thereto and a babbitt layer on the bronze, the babbitt layer preventing seizure of the bearing during operation and having the desired characteristic of embedability.

Still further, another object of this invention is to provide aprocess of producing a pump bushing comprising an aluminum member, a bronze surface thereon and a babbitt bearing surface on the bronze, the babbitt preventing seizure of the bearing face during operation and possessing the desiredcharacteristic of embedability.

A still further object of this invention is to provide a composite bearing structure comprising an aluminum housing, a bronze member bonded to the housing and a babbitt bearing surface bonded to the bronze.

' Still further, an object of this invention is, to provide an aluminum pump bushing having arbronze face bonded thereto and having a babbitt bearing surface bonded to the bronze face.

These and other objects and features of this invention will become. apparent from the following description when taken with the accompanying drawings showing the structure with the metal coatings being illustrated in exaggerated dimensions, and in which:

Figure 1 is a sectional view of a bearing member formed in accordance with this invention;

Figure 2 is an elevational view of the structure shown in Figure 1; and

Figure 3 is a sectional view of a pump bushing formed in accordance with this invention.

Reference is now made to Figures 1 and 2 wherein there is illustrated a lined bearing member comprising a housing or sleeve 10 of aluminum or an alloy composed mainly of aluminum, a bearing liner or bushing 11 of a copper-lead alloy, a flash or strike 12 of copper, a plating 13 of nickel on the housing and a bonding agent 14 of tin, bonding the housing and liner. Also, there is illustrated a layer 15 of babbitt on the liner or bushing 11.

As in our aforementioned co pending application, a suitable copper-lead alloy may consist of copper and 20% lead and a suitable aluminum alloy, known as 178, having a composition of 2.5% copper, 0.5% Mg, 0.5% Mn, balance Al may be used. It is, of course, understood that other alloys having suitable properties may be employed in lieu of the above. With regard to the babbitt, there are many compositions thereof each having'particular properties and the particular babbitt composition used depends upon the ultimate use of the article being produced.

In producing the structure thus described, the aluminum and bronze parts are first machined to the approximate shapes and the metals are prepared for bonding, as follows:

Preparation of the aluminum (1) Degrease to remove cutting oils.

(2) Etch in 10% caustic soda for 10 minutes at room temperature.

(3) Rinse in water at F.

(4) Dip in concentrated nitric acid from 5 to 10 seconds, or until all smut is removed.

(5) Rinse in cold water.

(6) Immerse in caustic zincate bath for 15 to 45 seconds. The work should be uniformly gray. If the work is spotty, repeat steps 4, 5 and 6.

(7) Rinse in cold water.

(8) Copper strike or flash.

(9) Rinse in cold water.

(10) Nickel plate 0.0002 inch in a Watts type nickel bath with no brightners.

(11) Rinse in cold water.

(12) Rinse in hot water.

(13) Dry.

(14) Apply a suitable flux to the metal and tin in molten tin at 550 to 700 F.

Preparation of the copper-lead liner (1) Clean and etch.

(2) Apply a suitable flux to the metal and tin in molten tin at 550 to 700 F.

The copper and nickel coatings on the aluminum member provide a surface to which tin will readily adhere, since aluminum cannot be tinned directly because of the aluminum oxide film which forms instantly when aluminum is exposed toair. The copper is flashed on to the aluminum for good adherence, and the nickel is plated therein to a thickness of at least 0.0002 inch. The usual thickness of the nickel plate is 0.0005 inch. Nickel is employed as a final plating on the aluminum member because it tins and does not go into solution with tin too rapidly, thus allowing time to heat the aluminum member, totinning temperature by immersion in a tin bath. No brightners are employed in the nickel bath since they tend to make the plated member brittle, which would adversely affect thestrength of the bond being produced. The usual fiux applied to the parts prior to tinning is a Du Pont product Eureka #55, a highly active and corrosive acid' chloride type. However, it should be understood that other fluxes may be employed in the process, and, it should further be noted that no flux is used after the parts are tinned; this latter procedure avoiding trapping of flux at the interface.

The temperature employed to tin the parts may be in the range of 550 to 700 F. When the tin pot is large, tempertaurw of 550 to 650 F. are usually employed. However, when the tin pot is small, that is, the volume of tin is relatively small, temperatures of 600 to 700 F. are advantageously employed because the, metal parts tend to extract heat from the molten tin very rapidly.

After the component parts are prepared and while they are maintained at a tempertaure of 550 to 700 F. and while the tinned surfaces are molten, the component parts are essembled. Additional tin may be melted and flowed between the parts and pressure employed, if necessary. Upon cooling of the assembled structure, the bond between the aluminum and bronze is completed, and the structure may then, and usually is, machined to final dimensions.

In the above description, the bonding material is referred to as being tin, and while it is generally pure tin, it must be understood that compositions composed mainly oftin may be employed in the process.

After the aluminum to bronze structure is machined to final dimensions, any oxides on the structure are removed by etching the structure in a dilute nitric sulphuric etching bath. The babbitt layer may then be cast, in a conventional manner, on to the bronze surface and is usually cast thereon to a thickness of approximately 0.125 inch. After casting the babbitt; the structure is chilled by quenching the:same inwater; at roomtemperature. The chilling operation determines the'structure of the babbitt layer. By quenching, the chilling accomplished rapidly, so that hard, antimony particles in the babbitt will remain suspended therein and not migrate toward the bottom of the layer as when chilling occurs at a relatively slow rate, as by chilling in-the ambient atmosphere. This results in a more uniform composition of the babbittt layer.

The completed structure may then be machined, so that there will be a micro layer of babbitt on the bronze bearing surface. This final babbitt layer usually has a thickness of 0.002 to 0.005 inch.

Figure 3 represents a pump bushing. structure as may be employed in a pressure loaded pump .of the type shown and described in US. Patent No. 2,420,622 to John A. Lauck et al. The bushing structure comprises a bushing member 16, of aluminum or an aluminum alloy and acopper-lead alloy face 17, a copper flasher strike 18, a nickel plate 19 and a bonding. agent 20, sucha-s tin. Also, there is shown a babbitt layer 21 bonded to the surface of the face 17. The parts are prepared and assembled in the same manner as set forth with regard to the Figures 1 and 2 embodiment, and the same alloys may be employed. In producing the bond between the aluminum and the bronze members in this embodiment, pressure is generally used to assure a perfect bond therebetween. While the tubular portion of the bushing is not illustrated as having the bronze and babbitt coatings thereon, it is to be understood that such coatings may be provided if necessary or desirable. These coatings may be internal or external on the tubular portion depending upon the operating conditions to be encountered.

While we have described our invention in. connection with two embodiments thereof, it. is to be understood that this is by way of illustration and not by way of limitation and ,the; scope of our invention, .isdefined solely -by the appended claims which should be construed as broadly as the prior art will'permit.

We claim:

1. A process of bonding an aluminum or aluminum alloy member to a copper-lead alloy member and babbitting said last-named member comprising, degreasing and cleaning the first-named member, providing the firstnamed member. with an electro-deposited layer of nickel, cleaning and etching said last-named member, providing the first and second-named members each with a layer comprising tin, assembling the members at a temperature in excess of the melting point of said layer comprising tin, and casting a layer of babbitt on said second-named member.

2. A process of bonding an aluminum or aluminum alloy member to a copper-lead alloy member and babbitting said last-named member comprising, degreasing and cleaning the first-named member, providing the firstnamed member with an electro-deposited layer of nickel, cleaning and etching said last-named member, applying a flux to each of said members, providing each of said fiuxed members with a layer comprising molten tin, assembling the members while the layer comprising tin is in molten condition, and casting a layer of'babbitt on said second-named'member.

3. A process of bonding an aluminum'or aluminum alloy member to a bronze member and babbitting said bronze member comprising, degreasing and cleaningthe first-named member, providing the first-named member with an electro-deposited layer of nickel having a thick ness of at least 0.0002 inch thick, cleaning and etching said bronze member, tinning said first-named member and said bronze member at a temperature of550 to 700 F., assembling the tinned members at a' temperature of 550 to 700 F., removing any oxide from said bonded members, and casting a layer-of babbitt on said bronze member;

, 4. A processof' bonding analuminum or aluminum alloy member to a bronze member and babbitting said bronze member comprising, degreasing and cleaning the first-named member, providing the first-named member with an electro-deposited layer of nickel having a thickness of at least 0.0002 inch, cleaning'and etching said bronze member, applying flux to said first-named and said bronze members, tinning said first-named and said bronze members at a temperature of 550 to 700 F., assembling the members at a temperature of 550 to 700 F., machining said bonded membersto approximately their final dimensions, removing any oxides from said bonded members, casting a layer of babbitt on said bronze member of the order of 0.125 inch, and machining said babbitt layerto a dimension-of the orderof 0.002 to 0.005 inch.

5. The method of constructing a-bearing having a housing of aluminum or its alloys; a liner of bronze and a layer of babbitt on said liner comprising the steps of providing the housing surface to be joined with an electrodeposited layer of'nickel having a thickness of at least 0.0002 inch, applying a flux to the surfaces of the housing and the liner to be joined, tinning the surfaces of the housing and the liner to be joined at a temperature of 550 to 700 F.-', assembling the tinned surfaces at a temperature of'SSO" to 700 F., and casting a layer of babbitt of the order of 0.125 inch on said liner.

6. A method of constructing apump bushing having a housing of aluminum or -its ,alloys, a facingof bronze and a babbitt plating on said facing comprising the steps of degreasing and cleaning the housing, providing the surface of the housing tobe joined with a layer of'nickel having a thickness of 'at least- 0.0002 inch, applyinga flux to said nickel plated surface, cleaning the surface of said bronze'faci ngto be joined, applying a flux to the cleaned facing, tinning the fiuxed surfaces of said housing and said facing, assembling the tinned surfaces at a temperature of 55 to 700 F., machining the bushing structure to'approximately'its final. dimensions,.- removing any oxides'onsaid bushing strncture,:casting a.laye1: ofbabbitt U on said bronze facing having a thickness of approximately 0.125 inch, rapidly quenching said babbitted structure, and machining said babbitt layer to the order of 0.002 to 0.005 inch.

7. A process of bonding an aluminum or aluminum alloy member to a bronze member and babbitting said last-named member comprising, providing the first-named member with a copper flash and a layer of nickel having a thickness of at least 0.0002 inch, tinning the first and second-named members at a temperature of 550 to 700 F, assembling the tinned members at a temperature of 550 to 7 F., and casting a layer of babbitt on said second-named member.

8. A process of bonding an aluminum or aluminum alloy member to a bronze member and babbitting said bronze member comprising, degreasing and cleaning the first-named member, providing the first-named member with a copper flash and an eleotro-deposited layer of nickel having a thickness of at least 0.0002 inch thick, cleaning and etching said bronze member, tinning said first-named member and said bronze member at a temperature of 550 to 700 F., assembling the tinned members at a temperature of 550 to 700 F., removing any oxide from said bonded members, and casting a layer of babbitt on said bronze member.

9. A process of bonding an aluminum or aluminum alloy member to a bronze member and babbitting said bronze member comprising, degreasing and cleaning the first-named member, providing the first-named member with a copper flash and an electro-deposited layer of nickel having a thickness of at least 0.0002 inch, cleaning and etching said bronze member, applying a flux to said firstnamed and said bronze members, tinning said first-named and said bronze members at a temperature of 550 to 700 F., assembling the members at a temperature of 550 to 700 F., machining said bonded members to approximately their final dimensions, removing any oxides from said bonded members, casting a layer of babbitt on said bronze member of the order of 0.125 inch, and machining said babbitt layer to a dimension of the order of between 0.002 to 0.005 inch.

-10. The method of constructing a bearing having a housing of aluminum or its alloys, a liner of bronze and a layer of babbitt on said liner comprising the steps of providing the housing surface to be joined with a copper flash and an electro-deposited layer of nickel having a thickness of at least 0.0002 inch, applying a flux to the surfaces of the housing and the liner to be joined, tinning the surfaces of the housing and the liner to be joined at a temperature of 550 to 700 -F., assembling the tinned surfaces at a temperature of 550 to 700 F., and casting a layer of babbitt of the order of 0.125 inch on said liner.

11. A method of constructing a pump bushing having a housing of aluminum or its alloys, a facing of bronze and a babbitt plating on said facing comprising the steps of degreasing and cleaning the housing, providing the surface of the housing to be joined with a copper flash and a layer of nickel having a thickness of at least 0.0002 inch, applying a flux to said nickel plated surface, cleaning the surface of said bronze facing to be joined, applying a flux to the cleaned facing, tinning the fluxed surfaces of said housing and said facing, assembling the tinned surfaces at a temperature of 550 to 700 F., machining the bushing structure to approximately its final dimensions, removing any oxides on said bushing structure, casting a layer of babbitt on said bronze facing having a thickness of approximately 0.125 inch, rapidly quenching said babbitted structure, and machining said babbitt layer to the order of 0.002 to 0.005 inch.

References Cited in the file of this patent UNITED STATES PATENTS 1,937,840 Pike Dec. 5, 1933 2,060,034 Chandler Nov. 10, 1936 2,095,837 Sandler Oct. 12, 1937 2,267,342 Schwartz Dec. 23, 1941 2,386,951 Howe Oct. 16, 1945 2,586,100 Schultz Feb. 19, 1952 2,621,988 Donley Dec. 16, 1952 2,658,266 Rose Nov. 10, 1953 2,682,702 Fink July 6, 1954 

1. A PROCESS OF BONDING AN ALUMINUM OR ALUMINUM ALLOY MEMBER TO A COPPER-LEAD ALLOY MEMBER AND BABBITTING SAID LAST-NAMED MEMBER COMPRISING, DEGREASING AND CLEANING THE FIRST-NAMED MEMBER, PROVIDING THE FIRSTNAMED MEMBER WITH AN ELECTRO-DEPOSITED LAYER OF NICKEL, 